Powered gas burners are heating devices that utilize a fan or blower to mix combustion air with gas from a supply and to direct the air/gas mixture to a burner tube at a pressure that is higher than atmospheric pressure. Powered burners are therefore distinguishable from atmospheric burners which rely solely on the static pressure of gas from a supply to provide an air/gas mixture at burner outlets where the air/gas mixture may be ignited to create a flame. Powered gas burners are also distinguishable from “induced draft” burners which utilize a fan at an exhaust location to create a negative pressure within the burner, thereby drawing additional airflow from the environment into the combustion chamber to mix with the gas from a supply. While such induced draft systems may be able to achieve higher ratios of air in the combustion chamber, these systems still rely upon available air from the environment and therefore may provide inconsistent efficiencies of combustion.
Powered burners are therefore capable of providing all of the air needed for combustion directly to the air/gas mixture exiting the burner outlets. Powered burners are generally used in heating appliances, such as, but not limited to, commercial cooking ovens and other systems where there is insufficient ambient air to ensure complete combustion. It is generally desirable to operate burner systems such that complete combustion of the air/gas mixture is achieved, as this provides efficient operation and high heat output. The optimum ratio of air and gas required for complete combustion is referred to as stoichiometric conditions. Powered burners are particularly advantageous in appliances such as ovens, griddles, grills, or furnaces, where the burner is disposed within an enclosure where a sufficient supply of atmospheric air is not available for complete combustion.
While various types of controllable burner systems are available, many conventional systems only regulate the flow of gas into a burner and therefore are not able to provide efficient combustion across the entire operating range of the appliance in which they are used. Other conventional systems are able to provide varied air and gas flow only at discreet, selected speeds, such as a high speed and a low speed. These systems are also not configured to provide efficient operation over the operating range between the high and low settings.
A need therefore exists for burner systems which are able to provide efficient combustion over the entire operating range of the appliances in which they are used.